Aromatic polycarbonate composition

ABSTRACT

An aromatic polycarbonate composition which contains 0.05 to 65 ppm of bonded phosphorus atoms to polycarbonate chains and free phosphorus compounds consisting of a tervalent phosphorus compound and a pentavalent phosphorus compound in a specific ratio. It is excellent in transparency, color stability and residence stability at the time of molding and is suitably used in disk substrates.

FIELD OF THE INVENTION

The present invention relates to an aromatic polycarbonate compositionand to an injection molded product thereof. More specifically, itrelates to an aromatic polycarbonate composition having excellenttransparency, color stability and residence stability during molding andto an injection molded product thereof.

PRIOR ART

A polycarbonate resin is excellent in optical properties, electricproperties and dimensional stability, and has self-extinguishingproperties and excellent mechanical properties such as impact resistanceand rupture strength, as well as excellent heat resistance andtransparency. Therefore, it is used for various purposes in largequantities. Making use of its transparency in particular, it is used inlenses, prisms, optical disks, sheets, films and the like in greatquantities.

Particularly for optical resin applications such as lenses and opticaldisks, excellent transparency and color are required of molded products.Stated more specifically, residence stability during the molding of aresin composition, particularly thermal stability and color stabilityduring residence, further moldability at the time of molding, that is,transferability and releasability which give precision molded productshaving a designed shape and size and further environmental stabilitysuch as wet heat durability are required of molded products.

To produce a molded product of a polycarbonate resin composition, afatty acid ester-based releasing agent has been used advantageously.This releasing agent is very effective in improving releasabilitybetween a metal mold and a molded product when a precision moldedproduct such as a disk is molded and suppresses reductions in thephysical properties such as color, transparency and surface propertiesof a molded product. However, the fatty acid ester-based compound ischaracterized that it has low heat resistance and is readily thermallydecomposed though it has relatively high releasability.

Particularly, a fatty acid ester-based releasing agent involves such aproblem that it decomposes at a molding temperature of a polycarbonateresin, particularly a temperature higher than 340° C., in the presenceof an acidic or basic compound or metal compound, thereby reducing itsreleasability or causing the color development of a molded product in anextreme case to contaminate a metal mold.

There are known methods of producing a polycarbonate resin: one in whichphosgene is directly reacted with an aromatic dihydroxy compound(interfacial polymerization method) and one in which an ester exchangereaction between an aromatic dihydroxy compound and a diaryl carbonatesuch as diphenyl carbonate is carried out in a molten state (meltingmethod).

To solve the above problem, the interfacial polymerization methodsucceeded in reducing impurities contained in a polycarbonate resin bymaking purification treatments on the resin and suppressing thedecomposition of the above releasing agent by using stabilizers to acertain extent.

However, due to the recent appearance of a new standard-based DVD disk,a substrate must be molded at a high temperature of 350° C. or higherthan that of the prior art and the decomposition and color developmentof the releasing agent or the resin composition at the time of formingthe substrate are becoming new problems to be solved.

In the melting method for producing a polycarbonate through an esterexchange reaction, general ester exchange catalysts are used asdisclosed by literature such as “Polycarbonate of Plastic MaterialLecture 17”, pp. 48-53 to improve production efficiency. It can be saidthat a catalyst system in which a nitrogen-containing basic compound ora phosphorus-containing basic compound and an alkali metal compound areused in combination out of the ester exchange catalysts is preferredbecause it improves the productivity and color of a polycarbonate resin,suppresses the formation of a branched structure in the polymermolecule, has excellent quality such as flowability and rarely formsforeign matter such as a gel.

However, a polycarbonate resin produced by the melt polymerizationmethod is unsatisfactory in terms of stability under a high-temperatureor oxidative atmosphere or hydrolytic conditions due to its secondaryreactivity derived from an alkali metal compound used as an esterexchange catalyst or additives. In addition, a releasing agent added asa precision molding aid cannot exhibit its own capability very oftencompared with a polycarbonate resin produced by the interfacialpolymerization method or its resin composition because the releasingagent causes the above decomposition or the like.

To solve these problems, JP-A 4-328124 and JP-A 4-328156 (the term“JP-A” as used herein means an “unexamined published Japanese patentapplication”) propose a method of neutralizing an ester exchangecatalyst with an acidic compound containing a sulfonic acid ester.

JP-A 8-59975 proposes use of a combination of a sulfonic acidphosphonium salt and a phosphorous acid ester-based compound orphenol-based antioxidant.

Further, JP-A 4-36346 discloses an aromatic polycarbonate-based resincomposition which contains 100 parts by weight of an aromaticpolycarbonate resin produced through an ester exchange reaction in amolten state between an aromatic organic dihydroxy compound and acarbonic acid diester in the presence of a catalytic system containing anitrogen-containing basic compound (a) and an alkali metal compound oralkali earth metal compound (b), or a catalytic system containing (a),(b) and boric acid or boric acid ester and 0.005 to 0.5 part by weightof a phosphorus-based antioxidant.

When a precision molded product is to be produced from the abovepolycarbonate resin produced by the melt polymerization method using afatty acid ester-based releasing agent, the releasing agent causes asecondary reaction such as decomposition and cannot exhibit expectedparting performance to the full, thereby causing frequently suchproblems as the deformation of a molded product, further the colordevelopment of the molded product and the great contamination of thesurface of the metal mold of a molding machine. Particularly, thistendency is marked under a high-temperature condition which is requiredfor the molding of a DVD substrate. The above defects are very seriousbecause they cause a transfer failure such as a groove or pit at thetime of forming a precision molded product such as an optical disk.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an aromaticpolycarbonate composition having excellent stability at the time of meltmolding.

It is another object of the present invention to provide an aromaticpolycarbonate composition which has excellent stability at the time ofmelt molding and suppresses decomposition and color development, areduction in its molecular weight and the formation of black foreignmatter at the time of melt molding.

It is still another object of the present invention to provide anaromatic polycarbonate composition which rarely contaminates a metalmold during molding and has excellent releasability from the metal mold.

It is a further object of the present invention to provide an aromaticpolycarbonate composition which is suitable for precision molding andhas excellent molding efficiency.

It is a still further object of the present invention to provide amolded product, particularly an injection molded product of the aromaticpolycarbonate composition of the present invention.

Other objects and advantages of the present invention will becomeapparent from the following description.

According to the present invention, firstly, the above objects andadvantages of the present invention are attained by an aromaticpolycarbonate composition comprising:

(A) 100 parts by weight of an aromatic polycarbonate

(1) which comprises mainly a recurring unit represented by the followingformula (1):

 wherein R¹, R², R³ and R⁴ are each independently a hydrogen atom, alkylgroup having 1 to 10 carbon atoms, aryl group having 6 to 10 carbonatoms or aralkyl group having 7 to 10 carbon atoms, and W is an alkylenegroup having 1 to 10 carbon atoms, alkylidene group having 2 to 10carbon atoms, cycloalkylene group having 6 to 10 carbon atoms,cycloalkylidene group having 6 to 10 carbon atoms,alkylene-arylene-alkylene group having 8 to 15 carbon atoms, oxygenatom, sulfur atom, sulfoxide group or sulfone group,

(2) which has a viscosity average molecular weight of 12,000 to 100,000,

(3) which has a molecular terminal OH group concentration of 3 to 80equivalents/ton of a polycarbonate resin (to be referred to as “eq/ton”hereinafter), and

(4) which contains bonded phosphorus atoms, which is phosphorus atomsbonded to a polycarbonate chain, in an amount of 0.05 to 65 ppm; and

(B) a combination of free P(III) compound and free P(V) compound ofwhich proportion satisfies the following expression:

0.1≦P(V)≦3×P(III)^(0.7)+2×(OH)^(0.2)

 wherein P(V) is the weight-based content (ppm) of the P(V) compound interms of phosphorus atoms, P(III) is the weight-based content (ppm) ofthe P(III) compound in terms of phosphorus atoms, and OH is theconcentration (eq/ton) of molecular terminal OH groups,

and which total 5×10⁻⁶ to 6.5×10⁻² parts by weight in terms ofphosphorus atoms; and

having (C) a melt viscosity change rate at 300° C. of 0.5% or less.

Secondly, the above objects and advantages of the present invention canbe attained by the above aromatic polycarbonate composition of thepresent invention.

In the present invention, the expression “bonded phosphorus atom” meansa phosphorus atom bonded to a polycarbonate chain and the expression“free phosphorus atom” means a phosphorus atom which is not bonded tothe polycarbonate chain.

DETAILED DESCRIPTION OF THE EMBODIMENT OF THE INVENTION

The aromatic polycarbonate used in the present invention essentiallyconsists of a recurring unit represented by the following formula (1):

wherein R¹, R², R³ and R⁴ are each independently a hydrogen atom, alkylgroup having 1 to 10 carbon atoms, aryl group having 6 to 10 carbonatoms or aralkyl group having 7 to 10 carbon atoms, and W is an alkylenegroup having 1 to 10 carbon atoms, alkylidene group having 2 to 10carbon atoms, cycloalkylene group having 6 to 10 carbon atoms,cycloalkylidene group having 6 to 10 carbon atoms,alkylene-arylene-alkylene group having 8 to 15 carbon atoms, oxygenatom, sulfur atom, sulfoxide group or sulfone group.

R¹, R², R³ and R⁴ in the above formula (1) are each independently anatom or group as defined hereinabove.

The alkyl group having 1 to 10 carbon atoms may be linear or branched,as exemplified by methyl, ethyl, propyl, butyl, octyl, decyl and thelike. Examples of the aryl group having 6 to 10 carbon atoms includephenyl, tolyl, cumyl, naphthyl and the like. Examples of the aralkylgroup having 7 to 10 carbon atoms include benzyl, 2-phenethyl,2-(2-methylphenyl)ethyl and the like.

R¹, R², R³ and R⁴ are each independently and preferably a hydrogen atom,methyl group or t-butyl group, particularly preferably hydrogen atom.

W is as defined hereinabove.

The alkylene group having 1 to 10 carbon atoms may be linear orbranched, as exemplified by methylene, 1,2-ethylene, 1,2-propylene,1,2-butylene, 1,10-decylene and the like.

Examples of the alkylidene group having 2 to 10 carbon atoms includeethylidene, propylidene, butylidene, hexylidene and the like.

Examples of the cycloalkylene group having 6 to 10 carbon atoms include1,4-cyclohexylene, 2-isopropyl-1,4-cyclohexylene and the like.

Examples of the cycloalkylidene group having 6 to 10 carbon atomsinclude cyclohexylidene, isopropylcyclohexylidene and the like.

Examples of the alkylene-arylene-alkylene group having 8 to 15 carbonatoms include an m-diisopropylphenylene group and the like.

W is preferably a cyclohexylidene group or 2,2-propylidene group,particularly preferably 2,2-propylidene group.

The aromatic polycarbonate contains the recurring unit represented bythe above formula (1) in an amount of 50 molt or more, preferably 70 mol% or more, particularly preferably 80 molt or more based on the total ofall the recurring units. One having ordinary skill in the art willunderstand recurring units which may be contained other than the aboverecurring unit represented by the above formula (1) from the followingdescription.

The aromatic polycarbonate used in the present invention has a viscosityaverage molecular weight of 12,000 to 100,000, preferably 13,000 to100,000, more preferably 13,000 to 70,000.

The aromatic polycarbonate used in the present invention has a molecularterminal OH group concentration of 3 to 80 eq/ton, preferably 5 to 70eq/ton, more preferably 10 to 50 eq/ton.

The aromatic polycarbonate used in the present invention furthercontains bonded phosphorus atoms, that is, phosphorus atoms bonded to apolycarbonate chain, in an amount of 0.05 to 65 ppm (based on weight),preferably 0.05 to 50 ppm, more preferably 0.05 to 30 ppm.

The above aromatic polycarbonate used in the present inventionpreferably has an acid value of 0 to 2 eq/ton. The ratio (Mw/Mn) ofweight average molecular weight (Mw) to number average molecular weight(Mn) is preferably 2.0 to 3.6, more preferably 2.2 to 3.4.

The aromatic polycarbonate used in the present invention may bepreferably produced from an aromatic dihydroxy compound and a carbonatebond forming compound by conventionally known methods such asinterfacial polymerization using phosgene, melt polymerization andsolid-phase polymerization.

The aromatic dihydroxy compound is preferably a compound represented bythe following formula (2):

wherein R¹, R², R³, R⁴ and W are as defined in the above formula (1).

Illustrative examples of the aromatic dihydroxy compound (2) includebis(4-hydroxyaryl)alkanes such as bis(4-hydroxyphenyl)methane,2,2-bis(4-hydroxyphenyl)propane, 1,1-bis(4-hydroxyphenyl)ethane,2,2-bis(4-hydroxy-3-methylphenyl)propane,2,2-bis(4-hydroxyphenyl)heptane,2,2-bis(4-hydroxy-3,5-dichlorophenyl)propane,bis(4-hydroxyphenyl)phenylmethane,4,4′-dihydroxyphenyl-1,1′-m-diisopropylbenzene and4,4′-dihydroxyphenyl-9,9-fluorene; bis(hydroxyaryl)cycloalkanes such as1,1-bis(4-hydroxyphenyl)cyclopentane,1,1-bis(4-hydroxyphenyl)cyclohexane,1-methyl-1-(4-hydroxyphenyl)-4-(dimethyl-4-hydroxyphenyl)methyl-cyclohexane,4-[1-[3-(4-hydroxyphenyl)-4-methylcyclohexyl]-1-methylethyl]phenol,4,4′-[1-methyl-4-(1-methylethyl)-1,3-cyclohexanediyl]bisphenol and2,2,2′,2′-tetrahydro-3,3,3′,3′-tetramethyl-1,1′-spirobis-[1H-indene]-6,6′-diol;dihydroxyaryl ethers such as bis(4-hydroxyphenyl)ether,bis(4-hydroxy-3,5-dichlorophenyl)ether and4,4′-dihydroxy-3,3′-dimethylphenyl ether; dihydroxydiaryl sulfides suchas 4,4′-dihydroxydiphenyl sulfide and4,4′-dihydroxy-3,3′-dimethyldiphenyl sulfide; dihydroxydiaryl sulfoxidessuch as 4,4′-dihydroxydiphenyl sulfoxide and4,4′-dihydroxy-3,3′-dimethyldiphenyl sulfoxide; dihydroxydiaryl sulfonessuch as 4,4′-dihydroxydiphenyl sulfone and4,4′-dihydroxy-3,3′-dimethyldiphenyl sulfone; dihydroxydiaryl isatinssuch as 4,4′-dihydroxydiphenyl-3,3′-isatin; dihydroxydiaryl xanthenessuch as 3,6-dihydroxy-9,9-dimethyl xanthene; dihydroxybenzenes such asresorcin, 5-methylresorcin, 5-ethylresorcin, 5-t-butylresorcin,5-phenylresorcin, 5-cumylresorcin, hydroquinone, 2-methylhydroquinone,2-ethylhydroquinone, 2-t-butylhydroquinone, 2-phenylhydroquinone and2-cumylhydroquinone; and dihydroxydiphenyls such as4,4′-dihydroxydiphenyl and 3,3′-dichloro-4,4′-dihydroxydiphenyl.

Out of these, 2,2-bis(4-hydroxyphenyl)propane is preferred because ithas stability as a monomer and a small content of impurities therein andcan be acquired easily.

In the present invention, at least one monomer may be optionallycontained in the molecule of the aromatic polycarbonate to control glasstransition temperature, improve flowability or control opticalproperties such as an increase in refractive index or a reduction inbirefringence.

Illustrative examples of the monomer include aliphatic dihydroxycompounds such as ethylene glycol, 1,4-butanediol, 1,4-cyclohexanedimethanol, 2,2-dimethyl-1,3-propanediol, 1,10-decanediol, diethyleneglycol, polyethylene glycol and polytetramethylene glycol; dicarboxylicacids such as succinic acid, isophthalic acid,2,6-naphthalenedicarboxylic acid, adipic acid, cyclohexanedicarboxylicacid and terephthalic acid; and oxyacids such as p-hydroxybenzoic acid,6-hydroxy-2-naphthoic acid and lactic acid.

A carbonyl halide such as phosgene or haloformate compound is used asthe carbonate bond forming compound in the phosgene method.

An aromatic carbonic acid ester such as diphenyl carbonate, ditolylcarbonate, bis(2-chlorophenyl)carbonate or m-cresyl carbonate is used asthe carbonate bond forming compound in the melt polymerization method.Also, dimethyl carbonate, dibutyl carbonate or dicyclohexyl carbonatemay be used as desired.

Out of these, diphenyl carbonate is particularly preferred from theviewpoints of reactivity, stability against the color development of theobtained resin and costs.

In the solid-phase polymerization method, an aromatic carbonate oligomerhaving a small molecular weight produced by the phosgene method or meltpolymerization method is crystallized and polymerized in a solid stateat a high temperature and optionally at a reduced pressure to produce anaromatic polycarbonate having a recurring unit structure represented bythe formula (1).

In the above aromatic polycarbonate production method, an aromaticpolyester carbonate can be produced by using a dicarboxylic acid or adicarboxylic acid derivative such as a dicarboxylic acid halide ordicarboxylic acid ester in conjunction with phosgene or carbonic aciddiester. This aromatic polyester carbonate may be used as the aromaticpolycarbonate in the present invention.

Illustrative examples of the dicarboxylic acid or dicarboxylic acidderivative include aromatic dicarboxylic acids such as terephthalicacid, isophthalic acid, terephthalic acid chloride, isophthalic acidchloride, diphenyl terephthalate and diphenyl isophthalate; aliphaticdicarboxylic acids such as succinic acid, glutaric acid, adipic acid,suberic acid, azelaic acid, sebacic acid, 1,10-decanedicarboxylic acid,1,12-dodecanedicarboxylic acid, adipic acid chloride, suberic acidchloride, azelaic acid chloride, sebacic acid chloride, diphenylazelate, diphenyl sebacate, diphenyl 1,10-decanedicarboxylate diphenyl1,12-dodecanedicarboxylate; and alicyclic dicarboxylic acids such ascyclopropanedicarboxylic acid, 1,3-cyclobutanedicarboxylic acid,1,3-cyclopentanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid,1,4-cyclohexanedicarboxylic acid; cyclopropanedicarboxylic acidchloride, 1,3-cyclobutanedicarboxylic acid chloride,1,3-cyclopentanedicarboxylic acid chloride, 1,3-cyclohexanedicarboxylicacid chloride, 1,4-cyclohexanedicarboxylic acid chloride; diphenylcyclopropane dicarboxylate, diphenyl 1,3-cyclobutane dicarboxylate,diphenyl 1,3-cyclopentane dicarboxylate, diphenyl 1,3-cyclohexanedicarboxylate and diphenyl 1,4-cyclohexane dicarboxylate.

To produce the aromatic polycarbonate having the recurring unitstructure represented by the above formula (1), a polyfunctionalcompound having three or more functional groups in one molecular may beused in conjunction with the above dihydroxy compound. Thepolyfunctional compound is preferably a compound having a phenolichydroxyl group or carboxyl group.

Illustrative examples of the polyfunctional compound include1,1,1-tris(4-hydroxyphenyl)ethane,2,2′,2″-tris(4-hydroxyphenyl)-m-diisopropylbenzene,2,2′,2″-tris(4-hydroxyphenyl)-p-diisopropylbenzene,α-methyl-α,α′,α′-tris(4-hydroxyphenyl)-1,4-diethylbenzene,α,α′,α′-tris(4-hydroxyphenyl)-1,3,5-triisopropylbenzene, phloroglucin,4,6-dimethyl-2,4,6-tris(4-hydroxyphenyl)-heptane,1,3,5-tris(4-hydroxyphenyl)benzene,2,2-bis[4,4-(4-hydroxyphenyl)-cyclohexyl]-propane, trimellitic acid,1,3,5-tricarboxybenzene, pyromellitic acid and the like.

Out of these, 1,1,1-tris(4-hydroxyphenyl)ethane andα,α′,α′-tris(4-hydroxyphenyl)-1,3,5-triisopropylbenzene are preferred.

When a polyfunctional compound is used in combination, it is used in anamount of 0.03 mol or less, preferably 0.00005 to 0.02 mol, morepreferably 0.0001 to 0.01 mol based on 1 mol of the aromatic dihydroxycompound to improve the melt viscosity of the polycarbonate.

In the present invention, the above aromatic polycarbonate has amolecular terminal OH group concentration of 3 to 80 eq/ton. Theterminals of the molecule of an aromatic polycarbonate produced by thephosgene method are capped by a monofunctional compound added as amolecular weight modifier to produce an aromatic polycarbonate having amolecular terminal OH group concentration of 3 to 20 eq/ton with ease.However, in the melt polymerization method or solid-phase polymerizationmethod, the concentration of molecular terminal OH groups must bereduced positively.

The concentration of molecular terminal OH groups is preferably 3 to 70eq/ton, more preferably 3 to 60 eq/ton.

The concentration of molecular terminal OH groups can be controlled tothe above range easily by using a terminal capping agent as a molecularweight modifier in the phosgene method. In the melt polymerization orsolid-phase polymerization method in which a terminal hydroxyl group isformed in large quantities by a reaction process, a special measure mustbe taken to reduce the concentration of terminal OH groups. For example,this can be attained by the following conventionally known methods.

1) method of controlling the molar ratio of charge stocks; The molarratio of a carbonate bond forming compound to an aromatic dihydroxycompound is increased at the time of charging for a polymerizationreaction. For example, this molar ratio is set to a range of 1.03 to1.10 in consideration of the characteristic features of a polymerizationreactor. Alternatively,

2) terminal capping method; At the end of a polymerization reaction,terminal OH groups are capped with a salicylic acid ester-based compoundin accordance with a method disclosed by U.S. Pat. No. 5,696,222. Theamount of the salicylic acid ester-based compound is preferably 0.8 to10 mols, more preferably 0.8 to 5 mols, particularly preferably 0.9 to 2mols based on 1 chemical equivalent of the terminal hydroxyl groupbefore a capping reaction. By adding the salicylic acid ester-basedcompound in that ratio, 80% or more of the terminal hydroxyl groups canbe capped advantageously. To carry out this capping reaction, catalystsenumerated in the description of the above patent are preferably used.

Illustrative examples of the salicylic acid ester-based compound include2-methoxycarbonylphenylaryl carbonates such as2-methoxycarbonylphenyl-phenylcarbonate,2-methoxycarbonylphenyl-4′-hexadecylphenyl carbonate,2-methoxycarbonylphenyl-cyclohexylphenyl carbonate,2-methoxycarbonylphenyl-cumylphenyl carbonate anddi(2-methoxycarbonylphenyl)carbonate; 2-methoxycarbonylphenyl-alkylcarbonates such as 2-methoxycarbonylphenyl-cetyl carbonate and2-methxoycarbonylphenyl-2′-(o-methoxycarbonylphenyl)oxycarbonylethylcarbonate; 2-ethoxycarbonylphenyl-aryl carbonates such as2-ethoxycarbonylpheny-phenyl carbonate anddi(2-ethoxycarbonylphenyl)carbonate; 2-ethoxycarbonylphenylalkylcarbonates such as 2-ethoxycarbonylphenyl-methyl carbonate;(2′-methoxycarbonylphenyl)esters of aromatic carboxylic acids such as(2-methoxycarbonylphenyl)benzoate and (2′-methoxycarbonylphenyl)4-(o-ethoxycarbonylphenyl)oxycarbonyl benzoate;(2′-ethoxycarbonylphenyl)esters of aromatic carboxylic acids such as(2-ethoxycarbonylphenyl)benzoate; and aliphatic carboxylic acid esterssuch as (2-methoxycarbonylphenyl)stearate andbis(2-methoxycarbonylphenyl)succinate.

In the method of producing an aromatic polycarbonate essentiallyconsisting of a recurring unit represented by the above formula (1), atertiary amine, quaternary ammonium salt, tertiary phosphine, quaternaryphosphonium salt, nitrogen-containing heterocyclic compound or saltthereof, iminoether or salt thereof, or a compound having an amide groupis used as a catalyst in the above phosgene method.

Since a large amount of an alkali metal compound or an alkali earthmetal compound is used as an agent for trapping a hydrogen halide suchas hydrochloric acid formed during a reaction in this phosgene method,it is preferred to carry out washing and purification thoroughly so asto prevent the above impurity from remaining in a polymer afterproduction.

In the melt polymerization and solid-phase polymerization methods, anester exchange catalyst containing an alkali metal compound or an alkaliearth metal compound is preferably used. The alkali metal compound oralkali earth metal compound used as the catalyst is used in an amount of1'10⁻⁸ to 1×10⁻⁶ equivalent in terms of an elemental metal based on 1mol of the aromatic dihydroxy compound. Above or below the above range,the alkali metal compound or alkali earth metal compound may exert a badinfluence upon the physical properties of the obtained aromaticpolycarbonate, an ester exchange reaction may not proceed fully, and anaromatic polycarbonate having a high molecular weight may not beobtained disadvantageously. An alkali metal compound is preferred as theester exchange catalyst.

When an alkali metal or alkali earth metal derived from the esterexchange catalyst contained in the aromatic polycarbonate is used in theabove range, the production of the aromatic polycarbonate can be carriedout efficiently at a high yield, and the physical properties of theobtained aromatic polycarbonate become preferred to attain the object ofthe present invention.

The alkali metal compound used as the ester exchange catalyst is, forexample, a hydroxide, hydrocarbon compound, carbonate, acetate, nitrate,nitrite, sulfite, cyanate, thiocyanate, stearate, borohydride, benzoate,hydrogenphosphate, bisphenol or phenol salt of an alkali metal.

Illustrative examples of the alkali metal compound include sodiumhydroxide, lithium hydroxide, sodium bicarbonate, potassium bicarbonate,sodium carbonate, cesium carbonate, sodium acetate, lithium acetate,rubidium nitrate, sodium nitrite, lithium nitrite, sodium sulfite,sodium cyanate, potassium cyanate, lithium cyanate, sodium thiocyanate,potassium thiocyanate, cesium thiocyanate, sodium stearate, sodiumborohydride, potassium borohydride, lithium borohydride, sodiumtetraphenylborate, sodium benzoate, lithium benzoate, disodiumhydrogenphosphate, salts of bisphenol A such as disodium salts,dilithium salts, monosodium salts, monopotassium salts, sodium potassiumsalts or sodium lithium salts of bisphenol A and sodium phenolate, orlithium phenolate.

A basic nitrogen compound and/or basic phosphorus compound are/ispreferably used in combination as an ester exchange catalyst.

Illustrative examples of the basic nitrogen compound include ammoniumhydroxides having an alkyl, aryl or alkylaryl group such as tetramethylammonium hydroxide (Me₄NOH), tetraethyl ammonium hydroxide (Et₄NOH),tetrabutyl ammonium hydroxide (Bu₄NOH), benzyltrimethyl ammoniumhydroxide (Ph—CH₂(Me)₃NOH) and hexadecyltrimethyl ammonium hydroxide;basic ammonium salts having alkyl, arylalkyl or alkylaryl group such astetramethyl ammonium acetate, tetraethyl ammonium phenoxide, tetrabutylammonium carbonate, benzyltrimethyl ammonium benzoate andhexadecyltrimethyl ammonium ethoxide; tertiary amines such astriethylamine, tributylamine, dimethylbenzylamine and hexadecyldimethylamine; and basic salts such as tetramethyl ammonium borohydride(Me₄NBH₄), tetrabutyl ammonium borohydride (BU₄NBH₄), tetrabutylammonium tetraphenyl borate (BU₄NBPh₄) and tetramethyl ammoniumtetraphenyl borate (Me₄NBPh₄).

Illustrative examples of the basic phosphorus compound includephosphonium hydroxides having an alkyl, aryl or alkylaryl group such astetramethyl phosphonium hydroxide (Me₄POH), tetraethyl phosphoniumhydroxide (Et₄POH), tetrabutyl phosphonium hydroxide (Bu₄POH),benzyltrimethyl phosphonium hydroxide (Ph—CH₂(Me)₃POH) andhexadecyltrimethyl phosphonium hydroxide; and basic salts such astetramethyl phosphonium borohydride (Me₄PBH₄), tetrabutyl phosphoniumborohydride (Bu₄PBH₄), tetrabutyl phosphonium tetraphenyl borate(BU₄PBPh₄) and tetramethyl phosphonium tetraphenyl borate (Me₄PBPh₄).

The basic nitrogen compound and/or basic phosphorus compound are/is usedin an amount of 1×10⁻⁵ to 5×10⁻⁴ chemical equivalent in terms of basicnitrogen atoms or basic phosphorus atoms based on 1 mol of the aromaticdihydroxy compound. The amount of the basic nitrogen compound and/orbasic phosphorus compound are/is more preferably 2×10⁻⁵ to 5×10⁻⁴chemical equivalent based on the same standard. The amount isparticularly preferably 5×10⁻⁵ to 5×10⁻⁴ chemical equivalent based onthe same standard.

The alkali metal compound used as a catalyst may be the ate-complexalkali metal salt of the group XIV element of the periodic table or thealkali metal salt of the oxo acid of the group XIV element of theperiodic table as desired. The group XIV element of the periodic tableis silicon, germanium or tin. By using the alkali metal compound as apolycondensation reaction catalyst, a polycondensation reaction canproceed quickly and completely. In addition, the alkali metal compoundcan control an undesired secondary reaction such as a branching reactionwhich proceeds during the polycondensation reaction to a low level.

What are enumerated in JP-A 7-268091 may be used as the ate-complexalkali metal salt of the group XIV element of the periodic table, asexemplified by NaGe(OMe)₅, NaGe(OPh)₅, LiGe(OMe)₅, LiGe(OPh)₅,NaSn(OMe)₃, NaSn(OMe)₅, NaSN(OPh)₅, and the like.

The alkali metal salt of the oxo acid of the group XIV element of theperiodic table is preferably the alkali metal salt of silicic acid,stannic acid, germanium (II) acid or germanium (IV) acid.

Illustrative examples of the above alkali metal salt include disodiumorthosilicate, disodium monostannate, tetrasodium monostannate,monosodium germanate(II) (NaHGeO₂), disodium orthogermanate(IV),tetrasodium orthogermanate(IV) and the like.

In the polycondensation reaction, at least one compound selected fromthe group consisting of oxo acids and oxides of the group XIV elementsof the periodic table and alkoxides and phenoxides of the same elementsmay be optionally existent as a co-catalyst together with the abovealkali metal compound catalyst.

By using the co-catalyst, undesired phenomena such as a branchingreaction which easily occurs during the polycondensation reaction, amain-chain cleavage reaction, the formation of foreign matter in theapparatus during molding and yellowing can be suppressed effectivelywithout reducing the rate of molecular terminal capping reaction and therate of polycondensation reaction.

The oxo acids of the group XIV elements of the periodic table includesilicic acid, stannic acid and germanic acid.

The oxides of the group XIV elements of the periodic table includesilicon dioxide, tin dioxide, germanium monoxide, germanium dioxide,silicon tetramethoxide, silicon tetrabutoxide, silicon tetraphenoxide,tetraethoxy tin, tetranonyloxy tin, tetraphenoxy tin, tetramethoxygermanium, tetrabutoxy germanium, tetraphenoxy germanium and condensatesthereof.

The co-catalyst is preferably existent in such a proportion that theamount of the group XIV element of the periodic table becomes 50 molaratoms or less based on 1 molar atom of an alkali metal element containedin the polycondensation reaction catalyst. When the co-catalyst is usedin such a proportion that the amount of the metal element is more than50 molar atoms, the polycondensation reaction slows downdisadvantageously. The co-catalyst is more preferably existent in such aproportion that the amount of the group XIV element of the periodictable becomes 0.1 to 30 molar atoms based on 1 molar atom of the alkalimetal element contained in the polycondensation reaction catalyst.

The aromatic polycarbonate composition of the present inventioncomprises 100 parts by weight of the aromatic polycarbonate used in thepresent invention and a combination of a free P(III) compound and a freeP (V) compound.

The P(III) compound is a phosphorous acid ester such as thoserepresented by the following formula.

Illustrative example of the P(III) compound include arylalkyl phosphitessuch as bis(2,4-di-t-butylphenyl)pentaerythrityl diphosphite,bis(2,6-di-t-butyl-4-methylphenyl)pentaerythrityl diphosphite,bis(nonylphenyl)pentaerythrityl diphosphite, diphenyldecyl phosphite,diphenylisooctyl phosphite, phenyldiisooctyl phosphite,2-ethylhexyldiphenyl phosphite, tetraphenylpropylene glycol diphosphite,tetrakis(tridecyl)-4,4′-isopropylidenediphenyl diphosphite,2,2-methylenebis(4,6-di-t-butylphenyl)octyl phosphite and2-{{2,4,8,10-tetrakis(1,1-dimethylethyl)dibenzo{d,f}{1,3,2}dioxaphosphepin-6-yl}oxy}-N,N-bis{2-{{2,4,8,10-tetrakis(1,1-dimethylethyl)dibenzo{d,f}{1,3,2}dioxaphosphepin-6-yl}oxy}-ethyl}ethanamine;trialkyl phosphites such as trimethyl phosphite, triethyl phosphite,tributyl phosphite, trioctyl phosphite, trinonyl phosphite, tridecylphosphite, trioctadecyl phosphite, distearyl pentaerythrityldiphosphite, bis(tridecyl)pentaerythrityl diphosphite,tris(2-chloroethyl)phosphite and tris(2,3-dichloropropyl)phosphite;tricycloalkyl phosphites such as tricyclohexyl phosphite; triarylphosphites such as triphenyl phosphite, tricresyl phosphite,tris(ethylphenyl)phosphite, tris(2,4-di-t-butylphenyl)phosphite,tris(nonylphenyl)phosphite and tris(hydroxyphenyl)phosphite;(hydrogenated bisphenol-A, pentaerythrityl phosphite polymer) and thelike.

Out of these, preferred are arylalkyl phosphites, particularlybis(2,4-t-butylphenyl)pentaerythrityl diphosphite, and triarylphosphites, particularly compounds represented by the following formula:

wherein R¹ is a t-butyl group, t-amyl group or cumyl group, and R² andR³ are each independently a hydrogen atom, t-butyl group, t-amyl groupor cumyl group, more particularly tris(2,4-di-t-butylphenyl)phosphite.The free P(III) compounds may be used alone or in combination of two ormore.

Illustrative example of P(V) compound include phosphorus acid esterexemplified by arylalkyl phosphates such asbis(2,4-di-t-butylphenyl)pentaerythrityl diphosphate, pentaerythrityl(2,4-di-t-butylphenyl)phosphate (2,4-di-t-butylphenyl)phosphite,bis(2,6-di-t-butyl-4-methylphenyl)pentaerythrityl diphosphate,pentaerythrityl(2,6-di-t-butyl-4-methylphenyl)phosphate(2,6-di-t-butyl-4-methylphenyl)phosphite,bis(nonylphenyl)pentaerythrityl diphosphate,pentaerythrityl(nonylphenyl)phosphate (nonylphenyl)phosphite,diphenyldecyl phosphate, diphenylisooctyl phosphate, phenyldiisooctylphosphate, 2-ethylhexyldiphenyl phosphate, tetraphenylpropylene glycoldiphosphate, propylene glycol diphenyl phosphate diphenyl phosphite,tetrakis(tridecyl)-4,4′-isopropylidenediphenyl diphosphate,4,4′-isopropylidenediphenyl bis(tridecyl)phosphatebis(tridecyl)phosphite and2,2-methylenebis(4,6-di-t-butylphenyl)octylphosphate; trialkylphosphates such as trimethyl phosphate, triethyl phosphate, tributylphosphate, trioctyl phosphate, trinonyl phosphate, tridecyl phosphate,trioctadecyl phosphate, distearyl pentaerythrityl diphosphate,pentaerythrityl stearyl phosphate stearyl phosphite,bis(tridecyl)pentaerythrityl diphosphate, pentaerythrityl tridecylphosphate, tridecyl phosphate, tris(2-chloroethyl)phosphate andtris(2,3-dichloropropyl)phosphate; tricycloalkyl phosphates such astricyclohexyl phosphate; triaryl phosphates such as triphenyl phosphate,tricresyl phosphate, tris(ethylphenyl)phosphate,tris(2,4-di-t-butylphenyl)phosphate, tris(nonylphenyl)phosphate andtris(hydroxyphenyl)phosphate; hydrogenated bisphenol-A, pentaerythritylphosphate polymers and the like.

Out of these, preferred are arylalkyl phosphates, particularlybis(2,4-di-t-butylphenyl)pentaerythrityl phosphate, and triarylphosphates, particularly compounds represented by the following formula:

wherein R¹ is a t-butyl group, t-amyl group or cumyl group, and R² andR³ are each independently a hydrogen atom, t-butyl group, t-amyl groupor cumyl group,

more particularly tris(2,4-di-t-butylphenyl)phosphate. The P(V)compounds may be used alone or in combination of two or more.

The free P(III) compound and the free P(V) compound contained in thepolycarbonate preferably have the same ester moiety skeleton.

The amounts of the above P(III) compound and P(V) compound satisfy thefollowing expression:

0.1≦P(V)≦3×P(III)^(0.7)+2×(OH)^(0.2)

preferably the following expression:

0.1×P(III)^(0.5)+0.03(OH)^(0.3)≦P(V)≦3×P(III)^(0.5)+2×(OH)^(0.2)

wherein P(V) is the weight-based content (ppm) of the P(V) compound interms of phosphorus atoms and P(III) is the weight-based content (ppm)of the P(III) compound in terms of phosphorus atoms.

These free phosphorus compounds are contained in a total amount of5×10⁻⁶ to 6.5×10⁻³ part by weight, preferably 1.0×10⁻⁵ to 5×10⁻³ part byweight, more preferably 5×10⁻⁵ to 4×10⁻³ part by weight in terms ofphosphorus atoms based on 100 parts by weight of the aromaticpolycarbonate.

Further, these free phosphorus compounds are contained in such a ratiothat satisfies the following expression (2):

0.1×P(III)^(0.5)+0.05×(OH)^(0.3)≦P(V)≦3×P(III)^(0.5)+1×(OH)^(0.2)

wherein P(V) and P(III) are as defined hereinabove and OH is theconcentration (eq/ton) of molecular terminal OH groups,

more preferably the following expression (2)-1:

0.1×P(III)^(0.5)+0.1×(OH)^(0.3)≦P(V)≦3×P(III)^(0.5)+1×(OH)^(0.2)  (2)-1.

The composition of the present invention contains bonded phosphorusatoms and the phosphorus atoms of the free phosphorus compounds in atotal amount of preferably 1.0×10⁻⁵ to 8.0×10⁻³ part by weight, morepreferably 2×10⁻⁵ to 7×10⁻³ part by weight based on 100 parts by weightof the above aromatic polycarbonate.

Further, the ratio of the bonded phosphorus atoms to the phosphorusatoms of the free phosphorus compounds in the composition of the presentinvention is preferably 1:4 to 4:1, more preferably 1:3 to 3:1.

A method, for example, to introduce the bonded phosphorus atoms to thearomatic polycarbonate is as follows.

Before the catalyst is deactivated and neutralized (polymerization endsupon the neutralization and deactivation of the catalyst), thephosphorus compounds are introduced into a reaction system to bondphosphorus atoms to the molecule of a polycarbonate for the productionof a polycarbonate.

These operations can be carried out easily using a polymerizationreactor or kneading extruder.

The atmosphere in which these operations are carried out is preferablyan atmosphere free from oxidation gas such as oxygen, at least at anoxygen concentration of 1 ppm or less.

When a kneading extruder is used, it is preferably pressurized withnitrogen gas to prevent oxygen from entering the extruder.

The free phosphorus compounds are mixed with an aromatic polycarbonateas follows, for example.

(1) With the same operation as that for the introduction of the abovebonded phosphorus atoms, the P(III) compound or P(V) compound is addedafter the end of polymerization of a polycarbonate, that is, thedeactivation of a polymerization catalyst, or

(2) after the P(III) compound is added in the same manner as in (1), apolycarbonate resin composition is oxidized in the air at a temperaturenear the glass transition temperature of a polycarbonate to adjust theamount of the free P(V) compound.

Since the oxidation time changes according to the size of apolycarbonate sample chip, oxidation is carried out while measuring theamount of the P(V) compound. This oxidation is preferably carried outfor 5 to 30 days, for example.

The composition of the present invention preferably contains an alkalimetal compound in an amount of 10 to 800 ppb in terms of an alkalimetal. The alkali metal compound is derived from the ester exchangecatalyst, co-catalyst or various additives added to the composition, allof which are used for the production of the aromatic polycarbonate.

The aromatic polycarbonate (A) of the present invention preferably has amelt viscosity stability of 0.5% or less. The melt viscosity stabilityis more preferably 0.3% or less, much more preferably 0.1% or less,particularly preferably 0%.

To control the melt viscosity stability to 0.5% or less, a meltviscosity stabilizer (E) is added in a specific amount to the aromaticpolycarbonate after the end of a polycondensation reaction, preferablyafter the end of a terminal capping reaction. An aromatic polycarbonatewhich is inferior in melt viscosity stability lacks stability duringmolding and experiences instability in mechanical properties,particularly marked deterioration or reduction in impact resistance, ata high humidity and when its molded product is used for a long time andhence, cannot be put to practical use.

The metal viscosity stabilizer used in the present invention ispreferably a compound represented by the following formula (3):

A¹—(SO₃X¹)_(m)  (3)

wherein A¹ is a hydrocarbon group having 1 to 20 carbon atoms which mayhave a substituent, X¹ is an ammonium cation, phosphonium cation oralkyl group having 1 to 10 carbon atoms, and m is an integer of 1 to 4.

Illustrative examples of the compound represented by the above formula(3) include phosphonium salts such as tetrabutylphosphoniumoctylsulfonate, tetramethylphosphonium benzenesulfonate,tetrabutylphosphonium benzenesulfonate, tetrabutylphosphoniumdodecylbenzenesulfonate and tetrabutylphosphonium p-toluenesulfonate;ammonium salts such as tetramethylammonium decylsulfonate andtetrabutylammonium dodecylbenzenesulfonate; and alkyl esters such asmethyl benzenesulfonate, butyl benzenesulfonate, methylp-toluenesulfonate, butyl p-toluenesulfonate and ethylhexadecylsulfonate.

Although the melt viscosity stabilizer is effective for a polycarbonateproduced by the phosgene method, it is used for a polycarbonate producedby the melt-polymerization or solid-phase polymerization method in anamount of preferably 0.7 to 100 equivalents, more preferably 0.8 to 30equivalents, much more preferably 0.9 to 20 equivalents, particularlypreferably 0.9 to 10 equivalents based on 1 equivalent of the alkalimetal compound of the ester exchange catalyst.

When a sulfonic acid alkyl ester is used out of the above melt viscositystabilizers, it is preferred to subject the aromatic polycarbonate to avacuum treatment. When the vacuum treatment is to be made, a treatmentdevice is not limited to a particular type. When a sulfonic acidphosphonium salt or sulfonic acid ammonium salt is used, it cannot besaid that it is preferred to subject the aromatic polycarbonate to thevacuum treatment.

The vacuum treatment is carried out in a vertical vessel type reactor,horizontal vessel type reactor, or vented single-screw or double-screwextruder at a reduced pressure of preferably 0.05 to 100 mmHg(6.65˜1.33×10⁴ Pa), more preferably 0.05 to 60 mmHg (6.65˜7.98×10³ Pa).

The vacuum treatment time is 5 minutes to 3 hours in the case of avessel type reactor and 5 seconds to 15 minutes in the case ofdouble-screw extruder. The treatment temperature is preferably 240 to350° C. The vacuum treatment can be carried out simultaneous withpelletizing with an extruder. The raw material monomer remaining in thearomatic polycarbonate is reduced or removed completely by carrying outthe above vacuum treatment.

The thus obtained aromatic polycarbonate has excellent moldability andresidence stability, and is particularly excellent in thermal stabilityand color stability, and advantageous to attain the object of thepresent invention.

A heat-resistant stabilizer does not have to be added to the aromaticpolycarbonate (A) of the present invention but an ordinaryheat-resistant stabilizer may be optionally added in limits that do notimpair the object of the present invention. The stabilizer is, forexample, a phosphorus-based stabilizer (other than the above meltviscosity stabilizers), steric hindered phenol-based stabilizer, organicthioether-based stabilizer or hindered amine-based stabilizer.

Examples of the phosphorus-based stabilizer include phosphonites such astetrakis(2,4-di-t-butylphenyl)-4,4-biphenylene diphosphonite,tetrakis(2,4-di-t-butylphenyl)-4,4′-phenylene diphosphinate and thelike. They may be used alone or in combination of two or more.

Examples of the steric hindered phenol-based stabilizer includen-octadecyl-3-(4′-hydroxy-3′,5′-di-t-butylphenyl)propionate,tetrakis{methylene-3-(3′,5′-di-t-butyl-4-hydroxyphenyl)propionate}methane,distearyl(4-hydroxy-3-methyl-5-t-butylbenzyl)malonate, triethyleneglycol-bis{3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate},1,6-hexanediol-bis(3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate),pentaerythrityltetrakis{3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate),2,2-thiodiethylenebis{3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate},2,2-thiobis(4-methyl-6-t-butylphenol),1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene,tris(3,5-di-t-butyl-4-hydroxybenzyl)-isocyanurate,2,4-bis{(octylthio)methyl}-o-cresol,isooctyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate,2,5,7,8-tetramethyl-2(4′,8′,12′-trimethyltridecyl)chroman-6-ol and thelike. They may be used alone or in combination of two or more.

Examples of the organic thioether-based stabilizer include dilaurylthiodipropionate, distearyl thiodipropionate,dimyristyl-3,3′-thiodipropionate, 1-ditridecyl-3,3′-thiopropionate,pentaerythritoltetrakis-(β-lauryl-thiopropionate) and the like. They maybe used alone or in combination of two or more.

Examples of the hindered amine-based stabilizer includebis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate,1-[2-{3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy}ethyl]-4-{3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy}-2,2,6,6-tetramethylpiperidine,4-benzoyloxy-2,2,6,6-tetramethylpiperidine,bis(1,2,2,6,6-pentamethyl-4-piperidyl)2-(3,5-di-t-butyl-4-hydroxybenzyl)-2-n-butyl malonate and the like. Theymay be used alone or in combination of two or more.

The heat-resistant stabilizer may be used in an amount of preferably0.0001 to 5 parts by weight, more preferably 0.0005 to 1 part by weight,much more preferably 0.001 to 0.5 part by weight based on 100 parts byweight of the aromatic polycarbonate.

A compound having at least one epoxy group in the molecule may be usedas an acidic substance trapping agent.

Illustrative examples of the acidic substance trapping agent includeepoxydated soybean oil, phenylglycidyl ether,3,4-epoxy-6-methylcyclohexylmethyl-3′,4′-epoxy-6′-methylcyclohexylcarboxylate, 3,4-epoxycyclohexylethylene oxide, bisphenol A diglycidylether, 2-ethylhexyl-3′,4′-epoxycyclohexyl carboxylate, 4,5-epoxytetrahydrophthalate anhydride and the like.

Out of these, alicyclic epoxy compounds are preferred, and3,4-epoxycyclohexylmethyl-3′,4′-epoxycyclohexyl carboxylate isparticularly preferred. The epoxy compound is added in an amount ofpreferably 1 to 2,000 ppm, more preferably 10 to 1,000 ppm based on thearomatic polycarbonate. The above epoxy compounds may be used alone orin combination of two or more.

The aromatic polycarbonate composition of the present invention mayfurther contain a releasing agent. The releasing agent is preferably ahigher fatty acid ester. The higher fatty acid ester is preferably apartial ester of a higher aliphatic carboxylic acid and a polyhydricalcohol. The high fatty acid ester is used in an amount of preferably0.005 to 0.5 part by weight, more preferably 0.007 to 0.5 part byweight, particularly preferably 0.01 to 0.3 part by weight based on 100parts by weight of the aromatic polycarbonate composition of the presentinvention. Sufficiently high heat resistance, releasability andmicron-order transfer are made possible by using the higher fatty acidester in the above range.

The expression “partial ester of an aliphatic carboxylic acid and apolyhydric alcohol” as used herein means a partial ester of an aliphaticcarboxylic acid and a polyhydric alcohol of which at least one hydroxylgroup is unreacted.

The higher aliphatic carboxylic acid is either a saturated orunsaturated higher aliphatic carboxylic acid. The higher aliphaticcarboxylic acid is preferably a saturated aliphatic carboxylic acid,particularly preferably a saturated aliphatic carboxylic acid having 12to 24 carbon atoms. When the number of carbon atoms is below the aboverange, the produced polycarbonate-based resin composition tends togenerate gas. When the number of carbon atoms is above the range, thereleasability of the polycarbonate-based resin composition is apt tolower. Examples of the higher aliphatic carboxylic acid includedodecanoic acid, palmitic acid, stearic acid, arachic acid, behenicacid, lignoceric acid and the like.

The polyhydric alcohol is not particularly limited and may be adivalent, trivalent, tetravalent, pentavalent or hexavalent alcohol. Forexample, it is preferably ethylene glycol, glycerin, trimethylol propaneand pentaerythritol, particuarly preferably glycerin.

The releasing agent is preferably a monoglyceride and/or diglyceride ofa saturated aliphatic monocarboxylic acid having 12 to 24 carbon atoms.

The partial ester of an aliphatic carboxylic acid and a polyhydricalcohol used in the present invention can be obtained through a generalesterification reaction.

Further, in the present invention, other conventionally known releasingagents may be used instead of or together with the above higher fattyacid ester releasing agents. Hydrocarbon releasing agents includenatural and synthetic paraffin waxes, polyethylene wax andfluorocarbons. Fatty acid releasing agents include higher fatty acidssuch as stearic acid and hydroxystearic acid, oxyfatty acids and thelike. Fatty acid amide releasing agents include fatty acid amides suchas stearic acid amide and ethylenebisstearyl amide, and alkylenebisfatty acid amides such as erucic acid amide.

Alcohol releasing agents include aliphatic alcohols such as stearylalcohol, polyhydric alcohols, polyglycols and polyglycerols.Polysiloxanes may also be used.

The aromatic polycarbonate composition of the present invention maycontain conventionally known additives such as an photo-stabilizer,ultraviolet light absorber, metal inactivating agent, quencher, metalsoap, nucleating agent, antistatic agent, flame retardant and colorantto attain desired purposes.

Examples of the photo-stabilizer include benzotriazole-based compoundssuch as 2-(3-t-butyl-2-hydroxy-5-methylphenyl)-5-chlorobenzotriazole,2-(3,5-di-t-butyl-2-hydroxyphenyl)benzotriazole,2-(2-hydroxy-5-t-octylphenyl)benzotriazole and2-{2-hydroxy-3-(3,4,5,6-tetrahydrophthalimidemethyl)phenyl}benzotriazole;benzophenone-based compounds such as 2-hydroxy-4-octyloxybenzophenone;and benzoate-based compounds such as 2,4-di-t-butylphenyl and3,5-di-t-butyl-4-hydroxy benzoate.

Examples of the ultraviolet light absorber include cyanoacrylate-basedcompounds such as ethyl 2-cyano-3,3-diphenyl acrylate.

These photo-stabilizer and ultraviolet light absorber may be used in anamount of preferably 0.001 to 5 parts by weight, more preferably 0.05 to1.0 part by weight, more preferably 0.01 to 0.5 part by weight based on100 parts by weight of the aromatic polycarbonate. These agents may beused alone or in combination.

Examples of the quencher include nickel-based quenchers such as nickeldibutyl dithiocarbamate.

Examples of the metal inactivating agent include compounds such asN,N′-(3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyl)hydrazine.

Examples of the metal soap include compounds such as calcium stearate.

Examples of the nucleating agent include sorbitol-based andphosphate-based compounds such as sodium di(4-t-butylphenyl)phosphonate,dibenzylidene sorbitol and methylenebis(2,4-di-t-butylphenol)acidphosphate sodium salt.

Examples of the antistatic agent include quaternary ammonium salt-basedcompounds such as lauramidepropyl)trimethyl ammonium sulfate and alkylphosphate-based compounds.

Examples of the flame retardant include halogen-containing phosphatessuch as tris (2-chloroethyl)phosphate, halides such ashexabromocyclododecane and decabromophenyl oxide, metal inorganiccompounds such as antimony trioxide, antimony pentoxide and aluminumhydroxide, and mixtures thereof.

The colorant may be an organic or inorganic dye or pigment as follows.

Examples of the inorganic colorant include oxides such as titaniumdioxide and iron oxide red, hydroxides such as alumina white, sulfidessuch as zinc sulfide, selenides, ferrocyanides such as iron blue,chromates such as zinc chromate and molybdenum red, sulfates such asbarium sulfate, carbonates such as calcium carbonate, silicates such asultramarine blue, phosphates such as manganese violet, carbon such ascarbon black, and metal colorants such as bronze powders and aluminumpowders.

Examples of the organic colorant include nitroso-based colorants such asNaphthol Green B, nitro-based colorants such as Naphthol Yellow S,azo-based colorants such as Naphthol Red and Chromophthal Yellow,phthalocyanine-based colorants such as Phthalocyanine Blue and Fast SkyBlue, and condensation polycyclic colorants such as Indanthrone Blue andQuinacridone Violet.

These colorants may be used alone or in combination. The colorant may beused in an amount of preferably 1×10⁻⁶ to 5 parts by weight, morepreferably 1×10⁻⁶ to 3 parts by weight, particularly preferably 1×10⁻⁵to 1 part by weight based on 100 parts by weight of the aromaticpolycarbonate.

The aromatic polycarbonate composition of the present invention can bemolded into various moldings. For example, to mold a disk substrate,general molding methods such as injection molding and compressionmolding, and other methods such as ultrasonic molding, multi-stagecompression molding and high-speed filling molding may be employed usinga metal mold for forming disks.

The molding temperature is preferably 300 to 390° C., more preferably310 to 350° C., and the temperature of the metal mold is preferably 75to 130° C. To reduce birefringence and improve transferability, thetemperature of the aromatic polycarbonate composition is preferably sethigh. When the molding temperature is higher than 390° C., it is worriedthat the thermal decomposition of the composition may occur andimpurities may be formed in a molded product, thereby reducingtransparency. Transparency is one of physical properties essential to asubstrate. The temperature of the metal mold is preferably higher toimprove flowability. When the temperature of the metal mold is 130° C.or more, a molded product may be warped and not usable as a substrate.

Further, the injection rate is preferably 150 cm³/sec or more, morepreferably 200 cm³/sec or more. When the injection rate is lower than150 cm³/sec, a molding material is quenched in the metal mold to augmentits flow pressure loss and resin alignment with the result that a moldedproduct may be distorted.

The material of the metal mold is not limited to a particular kind andmay be a metal, ceramic, graphite or the like. The substrate thus moldedcan be advantageously used as a substrate for read only, write only, andrewritable digital video disks. To produce a digital video disk usingthe substrate of the present invention, the same method as used in theproduction of a general compact disk can be employed.

In the film forming step, two laminates, each consisting of a substrate,a recording film and a protective film formed on the substrate, and ahard coat layer and optionally an overcoat layer formed on theprotective film are bonded together with an ultraviolet light curableresin adhesive in accordance with a commonly used method.

EXAMPLES

The following examples are provided for the purpose of furtherillustrating effects of the present invention but are in no way to betaken as limiting.

1) Measurement of Viscosity Average Molecular Weight of Polycarbonate

The intrinsic viscosity [η] of a polycarbonate is measured in methylenechlorine at 20° C. with an Ubbellohde viscometer and the viscosityaverage molecular weight of the polycarbonate is calculated from theintrinsic viscosity according to the following equation.

[η]=1.23×10−4MV^(0.83)

2) Concentration of Terminal Hydroxyl Groups

0.02 g of a sample is dissolved in 0.4 ml of bichloroform to measure theconcentrations of terminal hydroxyl groups and terminal phenyl groupsusing 1H NMR (of JEOL Ltd.; EX-270) at 20° C.

3) Melt Viscosity Stability

The absolute value of a change in melt viscosity measured with the RAAtype flow analyzer of Rheometrics Co., Ltd. under a nitrogen air streamat a shearing speed of 1 rad/sec and at 300° C. for 30 minutes afterchanges in melt viscosity become stable to obtain a change rate perminute. To obtain high long-term and short-term resin stabilities of thepolycarbonate, the value should not exceed 0.5%.

4) Analysis of Phosphorus

4)-(1) Analysis of All Phosphorus Atoms and Bonded Phosphorus Atoms;[P(III)+P(V)]

a) analysis of all phosphorus atoms; sample, polycarbonate

b) analysis of bonded phosphorus atoms; sample, polycarbonate afterextraction of soluble phosphorus atoms

1 to 2 g of each sample is accurately weighed and injected into a glassbeaker, about 1 ml of sulfuric acid of a reagent special grade, 20 to 30ml of nitric acid and evaporated at 30° C., condensed and dried up, and2.0 ml of a sililation reagent (BSTFA of Tokyo Kasei Kogyo Co., Ltd.) isadded to introduce trimethylsilyl into the polycarbonate. The obtainedproduct is transferred to a 5 ml graduated flask and acetonitrile (forhigh-speed liquid chromatography) is added to set the total quantity to5 ml. The obtained solution is analyzed by GC and GC/MS.

1.0 μl of a pretreated acetonitrile solution is injected into GC andanalyzed by elevating the temperature. The detected peak compound isidentified from the position of a detected peak and GC/MS analysis andthe quantity of the compound is determined from the area of the peak.analytical conditions device 5890 series II of Hewlett Packard Co., Ltd.integrator HP3396 series II of Hewlett Packard Co., Ltd. detector frameionization detector of Hewlett Packard Co., Ltd.

temperature 300° C.; column DB-5 (J & W) 5% phenylmethyl silicone;column length; 30 m, column diameter; 0.25 mm thickness of film; 0.1 μm;temperature; starting temperature of 100° C.; (maintained for 1.0 min),final temperature of 300° C.; (maintained for 10.0 min); temperatureelevation rate: 20° C./min; carrier gas flow rate of He; 60 ml/min;

5) Measurement of Acid Value

5)-(1) Polycarbonate Resin, Composition

About 1 g of a sample is accurately weighed and dissolved in 100 ml ofchloroform, diluted with benzyl alcohol to a volume of 100 ml. Theresulting solution is titrated about 1 ml of perchloric acid are addedto the glass beaker, and the resulting solution is heated on a hot plateat about 200° C. for 1 to 2 days to be decomposed until it becomesachromatic to light yellow in accordance with a commonly used method.(The nitric acid is added in an appropriate amount to prevent the samplefrom being dried up.)

The slightly wet decomposed product is dissolved in nitric acid of areagent special grade and injected into a 10 ml graduated flask todetermine its quantity. At the same time, a blank experimental liquid(reagent blank) is prepared by the same operation as the sample. Thequantity of phosphorus atoms contained in each sample: [P(III)+P(V)]contained in each sample is determined by correcting a blankexperimental value measured by ICP emission spectral analysis inaccordance with an absolute calibration curve method.

analytical conditions ICP emission spectral analyzer; SPS1200VR of SeikoInstruments Co., Ltd. measurement wavelength 177.50 nm plasma output 1.3kW photometering height 15 mm flow rate of plasma gas 16 l/min flow rateof nebulized gas 1.0 l/min flow rate of auxiliary gas 0.5 l/min

4-(2) Identification and Quantity Determination of Free PhosphorusAtoms; [P(III) and P(V)]

About 5 g of a PC sample is accurately weighed and injected in a 300 mlbeaker to be dissolved in 40 ml of methylene chloride (of a reagentspecial grade). Methanol (of a reagent special grade) is added dropwiseunder agitation with ultrasonic waves to set the total quantity to 150ml. The precipitated polycarbonate is separated by filtration (filter;No. 2 of Toyo Roshi Co., Ltd.), the filtrate is with a 0.01 N benzylalcohol solution of NaOH using phenol red as an indicator.

5)-(2) Additive

About 1 g of a sample is accuately weighed, dissolved in 100 ml ofbenzyl alcohol and titrated in the same manner as in (1). device; COOHmeasurement instrument (Model; COM-3) of Seiwa Gikenn Co., Ltd.

6) Residence Stability

A plate measuring 50 mm×50 mm×2 mm is formed into sample 1 with the M50Binjection molding machine of Meiki Seisakusho Co., Ltd. at a cylindertemperature of 380° C., a mold temperature of 750° C., an injectionpressure of 300 kg and a clamping force of 50 tons.

Thereafter, the sample is retained in a cylinder at the same temperaturefor 15 minutes to form sample 2.

The colors, L, a and b values of these two plates are measured with theZ-1001DP color difference meter of Nippon Denshoku Co., Ltd. to obtainΔE from the following equation.

ΔE=[L1−L2)²+(a1−a2)²+(b1−b2)²]^(½)

When the value ΔE is larger than 3, a change in the color of a moldedproduct becomes large by fluctuations in the molding conditions of themolded product and the commercial value of the molded product is greatlyimpaired.

To suppress a change in the color of the molded product, it is the bestthat the value ΔE should be “0”. When the value is 1 or less, the moldedproduct is excellent, when the value is 2.0 to less than 2.5, the moldedproduct is satisfactory, and when the value is 2.5 to less than 3.0, themolded product is acceptable.

7) Disk Releasability; Mold Stains

The obtained polycarbonate composition pellets are used, a moldexclusive for DVD is set in the DISK3 MIII of Sumitomo Heavy Industries,Ltd., a nickel DVD stamper which stores information such as an addresssignal is set in this mold, the above composition pellets are suppliedinto the hopper of a molding machine automatically, and 10K DVD disksubstrates having a diameter of 120 mm and a thickness of 0.6 mm areformed at a cylinder temperature of 380° C., a mold temperature of 115°C., an injection rate of 200 mm/sec and a holding pressure of 3,432 kPa(35 kgf/cm²).

When the number of disk substrates which could not removed from the moldsmoothly by an apparatus after molding is 10 or more, disk releasabilityis judged as X, when the number is 3 to 9, disk releasability is judgedas ∘, and when the number of 2 or less, disk releasability is judged as⊚.

Stains on the stamper after molding are checked with the eye. Whenstains on the stamper are hardly observed or very few, they are judgedas ⊚, when stains are few, they are judged as ∘, and when stains areobviously observed, they are judged as X.

1. Examples 1 to 14 18 and 19, Comparative Examples 1 to 6: MW=13,500

(Production Example of Polycarbonates)

22.8 parts by weight of bisphenol A, 22.0 parts by weight of diphenylcarbonate, 4×10⁻⁶ part by weight of NaOH as a polymerization catalyst,and 9.1×10⁻⁴ part by weight of tetramethyl ammonium hydroxide werecharged into a reactor equipped with a stirrer, a distillation columnand a vacuum generating equipment and dissolved at 140° C. after theinside of the reactor was substituted with nitrogen. After 30 minutes ofagitation, a reaction was carried out for 30 minutes by elevatingtemperature inside the reactor to 180° C. and reducing pressure insidethe reactor to 1.33×10⁴ Pa and the formed phenol was distilled off.

Thereafter, the reaction was continued for 30 minutes by graduallyincreasing the inside temperature to 200° C. and reducing the insidepressure to 0.67×10⁴ Pa while phenol was distilled off. The reaction wasfurther continued for 30 minutes by gradually elevating the temperatureto 220° C. and reducing the pressure to 4.0×10³ Pa. The reaction wasstill further continued by increasing the temperature and reducing thepressure to the three stage of 240° C. and 1.33×10³ Pa, 260° C. and1.33×10² Pa and 260° C. and 1.33×10² Pa or less, respectively.

Finally, the polymerization reaction was continued at the temperature of260° C. and the pressure of 1.33×10² Pa or less to obtain apolycarbonate resin having a viscosity average molecular weight of13,500. When part of the obtained polymer was sampled to measure itsconcentration of terminal hydroxyl groups, it was found to be 100eq/ton.

(Formation of Phosphorus Bonded PC)

Thereafter, phosphorus compounds A1 to A6 shown in the bonded P columnsof Tables 1 and 2 were added and reacted at 260° C. and 1.33×10⁴ Pa for10 minutes to obtain polycarbonate resins containing predeterminedamounts of bonded phosphorus shown in Tables 1 and 2.

(Adjustment of Terminal Hydroxyl Groups)

Predetermined amounts of 2-methoxycarbonylphenyl-phenyl-carbonate(abbreviated as SAMDPC) shown in the terminal capping agent columns ofTables 1 and 2 were added to the above polycarbonate resins having aterminal hydroxyl group concentration of 100 eq/ton at 0.67×10⁴ Pa and270° C. and then a terminal capping reaction was continued for 5 minutesat 270° C. and 1.33×10² Pa or less to obtain polycarbonate resins havinga concentration of terminal hydroxyl groups shown in Tables 1 and 2.

(Stabilization of Melt Viscosity)

8.8×10⁻⁵ part by weight (1.5 times the equivalent of an Na catalyst) ofpurified tetrabutylphosphonium dodecylbenzene sulfonate (abbreviated asDBSP) shown in the deactivator columns of Tables 1 and 2 was added as amelt viscosity stabilizer, mixed and stirred at the same temperature andthe same pressure for 10 minutes to deactivate and inactivate thecatalyst and polycarbonate resins having a viscosity average molecularweight of 13,500 (Examples 1 to 14, 18 and 19, Comparative Examples 1 to6) shown in Tables 1 and 2 were obtained.

(Production of Polycarbonate Resin Compositions: Addition of FreePhosphorus Compounds and Other Stabilizers)

The above obtained phosphorus-containing polycarbonates were suppliedinto a double-screw extruder by a gear pump, free phosphorus compoundsand a fatty acid ester as a releasing agent shown in Tables 3 to 6 wereadded under types and in amounts shown in Tables 3 to 6 to obtainpolycarbonate resin compositions (Examples 1 to 14, 18 and 19,Comparative Examples 1 to 6) shown in Tables 3 to 6. The polycarbonateresin compositions were extruded into chips. The amounts of the addedfree phosphorus compounds shown in Tables 3 and 4 were based on 25.4parts by weight of a polycarbbnate.

2. Examples 15 to 17: MW=15,000, 22,000, 30,000

Polycarbonate resins having respective molecular weights were producedin accordance with the above production examples of polycarbonates andbonded phosphorus was introduced by the compounds shown in Table 2 inthe same manner as described above to obtain three differentpolycarbonate resins shown in Table 7 below.

TABLE 7 Example viscosity average concentration of No. molecular weightterminal OH groups 15 15,000 95 16 22,000 70 17 30,000 55

The concentration of terminal hydroxyl groups was adjusted by thecompounds shown in Table 2 in the same manner as described above tostabilize melt viscosity and free phosphorus compounds, fatty acid esterand phenol-based stabilizer shown in Tables 4 and 6 were added undertypes and in amounts shown in Tables 4 and 6 to obtain polycarbonateresin compositions (Examples 15 to 17) shown in Tables 4 and 6.

3. Evaluation of Polycarbonate Resin Compositions

The above obtained polycarbonate resin compositions (Examples 1 to 19,Comparative Examples 1 to 6) were measured for their physical propertiesas shown in Tables 5 and 6. Further, disk substrates were formed andevaluated in accordance with the above methods.

TABLE 1 viscosity average catalyst: parts by deactivator: parts byterminal: parts by terminal molecular weight weight weight capping agentweight OH Ex. 1 13500 NaOH; 4.0 × 10⁻⁶ DBSH; 8.8 × 10⁻⁵ SAMDPC; 4.88 ×10⁻¹ 40 TMAH; 9.1 × 10⁻⁴ C. Ex. 1 13500 NaOH; 4.0 × 10⁻⁶ DBSH; 8.8 ×10⁻⁵ SAMDPC; 4.88 × 10⁻¹ 40 TMAH; 9.1 × 10⁻⁴ C. Ex. 2 13500 NaOH; 4.0 ×10⁻⁶ DBSH; 8.8 × 10⁻⁵ SAMDPC; 4.88 × 10⁻¹ 40 TMAH; 9.1 × 10⁻⁴ Ex. 213500 NaOH; 4.0 × 10⁻⁶ DBSH; 8.8 × 10⁻⁵ SAMDPC; 4.88 × 10⁻¹ 40 TMAH; 9.1× 10⁻⁴ Ex. 3 13500 NaOH; 4.0 × 10⁻⁶ DBSH; 8.8 × 10⁻⁵ SAMDPC; 4.88 × 10⁻¹40 TMAH; 9.1 × 10⁻⁴ C. Ex. 3 13500 NaOH; 4.0 × 10⁻⁶ DBSH; 8.8 × 10⁻⁵SAMDPC; 4.88 × 10⁻¹ 40 TMAH; 9.1 × 10⁻⁴ Ex. 4 13500 NaOH; 4.0 × 10⁻⁶DBSH; 8.8 × 10⁻⁵ SAMDPC; 4.88 × 10⁻¹ 40 TMAH; 9.1 × 10⁻⁴ Ex. 5 13500NaOH; 4.0 × 10⁻⁶ DBSH; 8.8 × 10⁻⁵ SAMDPC; 4.88 × 10⁻¹ 40 TMAH; 9.1 ×10⁻⁴ C. Ex. 4 13500 NaOH; 4.0 × 10⁻⁶ DBSH; 8.8 × 10⁻⁵ SAMDPC; 4.88 ×10⁻¹ 40 TMAH; 9.1 × 10⁻⁴ Ex. 6 13500 NaOH; 4.0 × 10⁻⁶ DBSH; 8.8 × 10⁻⁵SAMDPC; 4.88 × 10⁻¹ 40 TMAH; 9.1 × 10⁻⁴ Ex. 7 13500 NaOH; 4.0 × 10⁻⁶DBSH; 8.8 × 10⁻⁵ SAMDPC; 4.88 × 10⁻¹ 40 TMAH; 9.1 × 10⁻⁴ Ex. 8 13500NaOH; 4.0 × 10⁻⁶ DBSH; 8.8 × 10⁻⁵ SAMDPC; 4.88 × 10⁻¹ 40 TMAH; 9.1 ×10⁻⁴ melt viscosity stability Mw/Mn acid value bonded P: parts by weightbonded P (ppm) Ex. 1 0 2.2 0 A1; 5.48 × 10⁻⁴ 1 C. Ex. 1 0 2.2 0 A1; 5.48× 10⁻⁴ 1 C. Ex. 2 0 2.2 0 A2; 2.67 × 10⁻⁴ 1 Ex. 2 0 2.2 0 A2; 1.79 ×10⁻⁴ 0.7 Ex. 3 0 2.2 0 A3; 1.28 × 10⁻⁴ 0.5 C. Ex. 3 0 2.2 0 0 0 Ex. 4 02.2 0 A4; 7.21 × 10⁻⁴ 2 Ex. 5 0 2.2 0 A5; 1.73 × 10⁻³ 3.5 C. Ex. 4 0 2.20 A6; 1.51 × 10⁻³ 3.9 Ex. 6 0 2.2 0 A1; 1.10 × 10⁻³ 2 Ex. 7 0 2.2 0 A1;1.10 × 10⁻³ 2 Ex. 8 0 2.2 0 A2; 6.68 × 10⁻⁴ 2.5 Ex. = Example C. Ex. =Comparative Example

TABLE 2 viscosity average catalyst: parts by deactivator: parts byterminal: parts by terminal molecular weight weight weight capping agentweight OH Ex. 9 13500 NaOH; 4.0 × 10⁻⁶ DBSH; 8.8 × 10⁻⁵ SAMDPC; 4.88 ×10⁻¹ 40 TMAH; 9.1 × 10⁻⁴ Ex. 10 13500 NaOH; 4.0 × 10⁻⁶ DBSH; 8.8 × 10⁻⁵SAMDPC; 4.88 × 10⁻¹ 40 TMAH; 9.1 × 10⁻⁴ Ex. 11 13500 NaOH; 4.0 × 10⁻⁶DBSH; 8.8 × 10⁻⁵ SAMDPC; 4.88 × 10⁻¹ 40 TMAH; 9.1 × 10⁻⁴ Ex. 12 13500NaOH; 4.0 × 10⁻⁶ DBSH; 8.8 × 10⁻⁵ SAMDPC; 4.88 × 10⁻¹ 40 TMAH; 9.1 ×10⁻⁴ C. Ex. 5 13500 NaOH; 4.0 × 10⁻⁶ DBSH; 0 SAMDPC; 4.88 × 10⁻¹ 40TMAH; 9.1 × 10⁻⁴ Ex. 13 13500 NaOH; 4.0 × 10⁻⁶ DBSH; 8.8 × 10⁻⁵ SAMDPC;4.88 × 10⁻¹ 40 TMAH; 9.1 × 10⁻⁴ Ex. 14 13500 NaOH; 4.0 × 10⁻⁶ DBSH; 8.8× 10⁻⁵ SAMDPC; 2.44 × 10⁻¹ 70 TMAH; 9.1 × 10⁻⁴ C. Ex. 6 13500 NaOH; 4.0× 10⁻⁶ DBSH; 8.8 × 10⁻⁵ SAMDPC; 0 100  TMAH; 9.1 × 10⁻⁴ Ex. 15 15000NaOH; 4.0 × 10⁻⁶ DBSH; 8.8 × 10⁻⁵ SAMDPC; 4.47 × 10⁻¹ 40 TMAH; 9.1 ×10⁻⁴ Ex. 16 22000 NaOH; 4.0 × 10⁻⁶ DBSH; 8.8 × 10⁻⁵ SAMDPC; 3.25 × 10⁻¹30 TMAH; 9.1 × 10⁻⁴ Ex. 17 30000 NaOH; 4.0 × 10⁻⁶ DBSH; 8.8 × 10⁻⁵SAMDPC; 2.84 × 10⁻¹ 20 TMAH; 9.1 × 10⁻⁴ Ex. 18 13500 NaOH; 4.0 × 10⁻⁶DBSH; 8.8 × 10⁻⁵ SAMDPC; 6.50 × 10⁻¹ 20 TMAH; 9.1 × 10⁻⁴ Ex. 19 13500NaOH; 4.0 × 10⁻⁶ DBSH; 8.8 × 10⁻⁵ SAMDPC; 6.50 × 10⁻¹ 20 TMAH; 9.1 ×10⁻⁴ melt viscosity stability Mw/Mn acid value bonded P: parts by weightbonded P (ppm) Ex. 9 0 2.2 0 A3; 2.55 × 10⁻⁴ 1 Ex. 10 0 2.2 0 A3; 1.53 ×10⁻³ 6 Ex. 11 0 2.2 0 A2; 8.02 × 10⁻⁴ 3 Ex. 12 0 2.2 0 A1; 9.86 × 10⁻⁴1.8 C. Ex. 5 1.7 2.2 0 A1; 9.86 × 10⁻⁴ 1.8 Ex. 13 0 2.2 0 A1; 1.10 ×10⁻³ 2 Ex. 14 0 2.2 0 A1; 1.10 × 10⁻³ 2 C. Ex. 6 0 2.2 0 A1; 1.10 × 10⁻³2 Ex. 15 0 2.3 0 A2; 2.68 × 10⁻⁴ 1 Ex. 16 0 2.5 0 A2; 1.07 × 10⁻³ 4 Ex.17 0 3.0 0 A2; 2.14 × 10⁻³ 8 Ex. 18 0 2.2 0 A4; 7.21 × 10⁻⁴ 2 Ex. 19 02.2 0 A4; 7.21 × 10⁻⁴ 2 Ex. = Example C. Ex. = Comparative Example

TABLE 3 free total phosphorus bonded P: free P (III): free P (III) freeP (V): free P (V) P (ppm) free P parts by weight (ppm) parts by weight(ppm) P (III)/(V) Ex. 1 6 5 1/5 A1; 2.73 × 10⁻⁴ 0.5 B1; 2.53 × 10⁻³ 4.51/9 C. Ex. 1 5 4 1/4 A1; 2.19 × 10⁻³ 4 0 0  0/10 C. Ex. 2 5 4 1/4 0 0B1; 2.25 × 10⁻³ 4 10/0  Ex. 2 5 3 0.7/3   A2; 7.22 × 10⁻⁴ 2.7 B2; 8.4 ×10⁻⁵ 0.3 9/1 Ex. 3 5 5  1/10 A3; 1.15 × 10⁻³ 4.5 B3; 1.35 × 10⁻⁴ 0.5 9/1C. Ex. 3 5 5 A3; 7.67 × 10⁻⁴ 3 B3; 5.38 × 10⁻⁴ 2 3/2 Ex. 4 4 2 1/1 A4;6.49 × 10⁻⁴ 1.8 B4; 7.18 × 10⁻⁵ 0.2 9/1 Ex. 5 4 0.5 3.5/0.5 A5; 2.22 ×1⁻⁴ 0.45 B5; 2.60 × 10⁻⁵ 0.05 9/1 C. Ex. 4 4 0.09 3.9/0.1 A6; 3.5 × 10⁻⁶0.009 B6; 3.36 × 10⁻⁵ 0.081 9/1 Ex. 6 6 4 2/4 A1; 5.48 × 10⁻⁴ 1 B1; 1.68× 10⁻³ 3 1/3 Ex. 7 7 5 2/5 A1; 1.64 × 10⁻³ 3 B1; 1.12 × 10⁻³ 2 3/2 Ex. 85 3.5 5/7 A2; 8.29 × 10⁻⁴ 3.1 B2; 1.12 × 10⁻⁴ 0.4 3.1/0.4 Ex. = ExampleC. Ex. = Comparative Example

TABLE 4 free total phosphorus bonded P: free P (III): free P (III) freeP (V): free P (V) P (ppm) free P parts by weight (ppm) parts by weight(ppm) P (III)/(V) Ex. 9 4 3 1/3 A3; 2.56 × 10⁻⁴ 1 B3; 5.38 × 10⁻⁴ 2 1/2Ex. 10 8 2 3/1 A3; 3.83 × 10⁻⁴ 1.5 B3; 1.35 × 10⁻⁴ 0.5 3/1 Ex. 11 4 13/1 A2; 1.61 × 10⁻⁴ 0.6 B2; 1.12 × 10⁻⁴ 0.4 3/1 Ex. 12 0.7 1.8/0.7 A1;1.64 × 10⁻⁴ 0.3 B1; 2.24 × 10⁻⁴ 0.4 3/4 C. Ex. 5 2.5 0.7 1.8/0.7 A1;1.64 × 10⁻⁴ 0.3 B1; 2.24 × 10⁻⁴ 0.4 3/4 Ex. 13 5 3 1/2 A1; 8.22 × 10⁻⁴1.5 B1; 8.42 × 10⁻⁴ 1.5 1/1 Ex. 14 5 3 1/2 A1; 8.22 × 10⁻⁴ 1.5 B1; 8.42× 10⁻⁴ 1.5 1/1 C. Ex. 6 5 3 1/2 A1; 8.22 × 10⁻⁴ 1.5 B1; 8.42 × 10⁻⁴ 1.51/1 Ex. 15 5 4 1/4 A2; 5.35 × 10⁻⁴ 2 B25.61 × 10⁻⁴ 2 1/1 Ex. 16 10 6 1/3A2; 8.02 × 10⁻⁴ 3 B2; 8.43 × 10⁻⁴ 3 1/1 Ex. 17 20 12 1/3 A2; 1.61 × 10⁻³6 B2; 1.68 × 10⁻³ 6 1/1 Ex. 18 5 3 1/2 A4; 5.41 × 10⁻⁴ 1.5 B4; 5.38 ×10⁻⁴ 1.5 1/1 Ex. 19 5 3 1/2 A4; 5.41 × 10⁻⁴ 1.5 B4; 5.38 × 10⁻⁴ 1.5 1/1Ex. = Example C. Ex. = Comparative Example

TABLE 5 melt fatty acid phenol-based acid viscosity overall residencemold ester stabilizer value stability judgment stability; ΔEreleasability stains Ex. 1 (R2); 200 ppm 0 0 0 ◯ 2.3 ◯ ◯ C. Ex. 1 (R2);200 ppm 0 0 0 × 2.8 × × C. Ex. 2 (R2); 200 ppm 0 0 0 × 2.9 × × Ex. 2(R2); 200 ppm 0 0 0 ◯ 2.2 ◯ ◯ Ex. 3 (R2); 200 ppm 0 0 0 ◯ 2.4 ◯ ◯ C. Ex.3 (R2); 200 ppm 0 0 0 × 3.5 ◯ ◯ Ex. 4 (R3); 100 ppm 0 0 0 ◯ 1.8 ◯ ◯ Ex.5 (R3); 100 ppm 0 0 0 ◯ 2.7 ◯ ◯ C. Ex. 4 (R3); 100 ppm 0 0 0 × 3.7 × ×Ex. 6 (R1); 200 ppm 0 0 0 ⊚ 1.7 ⊚ ⊚ Ex. 7 (R1); 200 ppm 0 0 0 ⊚ 1.7 ⊚ ⊚Ex. 8 (R1); 200 ppm 0 0 0 ⊚ 1.5 ⊚ ⊚ Ex. = Example C. Ex. = ComparativeExample

TABLE 6 melt fatty acid phenol-based acid viscosity overall residencemold ester stabilizer value stability judgment stability; ΔEreleasability stains Ex. 9 (R1); 200 ppm 0 0 0 ⊚ 1.8 ⊚ ⊚ Ex. 10 (R1);200 ppm 0 0 0 ⊚ 1.6 ⊚ ⊚ Ex. 11 (R1); 200 ppm 0 0 0 ⊚ 1.8 ⊚ ⊚ Ex. 12(R1); 200 ppm 0 0 0 ⊚ 1.9 ⊚ ⊚ C. Ex. 5 (R1); 200 ppm 0 0 0.8 × 3.1 × ×Ex. 13 (R4); 300 ppm 0 0 0 ⊚ 1.7 ⊚ ⊚ Ex. 14 (R4); 300 ppm 0 0 0 ◯ 2.2 ◯⊚ C. Ex. 6 (R4); 300 ppm 0 0 0 × 3.6 × ◯ Ex. 15 (R5); 200 ppm C1; 100 00 ⊚ 1.9 ⊚ ⊚ C2; 200 Ex. 16 (R5); 200 ppm C1; 100 0 0 ⊚ 1.8 ⊚ ⊚ C2; 200Ex. 17 (R5); 200 ppm C1; 100 0 0 ◯ 2.2 ⊚ ⊚ C2; 200 Ex. 18 (R1); 200 ppm0 0 0 ⊚ 1.8 ⊚ ⊚ Ex. 19 (R1); 200 ppm 0 3 0 ◯ 2.4 ◯ ◯ Ex. = Example C.Ex. = Comparative Example

Abbreviations in the above Tables stand for the following substances.

P(III) compounds; (A1); tris(2,4-di-t-butylphenyl)phosphite, (A2);bis(2,6-di-t-butyl-4-methyl)pentaerythrityl diphosphite, (A3);bis(2,4-di-t-butylphenyl)pentaerythrityl diphosphite, (A4);bis(2,4-dicumylphenyl)pentaerythrityl diphosphite, (A5);2,2-methylenebis(4,6-di-t-butylphenyl)octylphosphite, (A6);bis(2,4-di-t-butylphenyl)acid pohsophite P(V) compounds; (B1);tris(2,4-di-t-butylphenyl)phsophate, (B2);bis(2,6-di-t-butyl-4-methyl)pentaerythrityl diphosphate, (B3);bis(2,4-di-t-butylphenyl)pentaerythrityl diphosphate, (B4);bis(2,4-dicumylphenyl)pentaerythrityl diphosphate fatty acid esters;(R1); glycerine monostearate, (R2); glycerine distearate, (R3);glycerine tristearate, (R4); pentaerythritol monostearate, (R5);pentaerythritol tetrastearate steric hindrance phenol-based stabilizers;(C1); 2-t-butyl-6-(3-t-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenylacryalte, (C2);pentaerythrityl-tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]

What is claimed is:
 1. An aromatic polycarbonate composition comprising:(A) 100 parts by weight of an aromatic polycarbonate (1) which comprisesmainly a recurring unit represented by the following formula (1):

 wherein R¹, R², R³ and R⁴ are each independently a hydrogen atom, alkylgroup having 1 to 10 carbon atoms, aryl group having 6 to 10 carbonatoms or aralkyl group having 7 to 10 carbon atoms, and W is an alkylenegroup having 1 to 10 carbon atoms, alkylidene group having 2 to 10carbon atoms, cycloalkylene group having 6 to 10 carbon atoms,cycloalkylidene group having 6 to 10 carbon atoms,alkylene-arylene-alkylene group having 8 to 15 carbon atoms, oxygenatom, sulfur atom, sulfoxide group or sulfone group, (2) which has aviscosity average molecular weight of 12,000 to 100,000, (3) which has amolecular terminal OH group concentration of 3 to 80 equivalents/ton ofa polycarbonate resin (to be referred to as “eq/ton” hereinafter), and(4) which contains bonded phosphorus atoms, which are phosphorus atomsbonded topolycarbonate chains, in an amount of 0.05 to 65 ppm; and (B) acombination of free P(III) compound and free P(V) compound which satisfythe following expression: 0.1≦P(V)≦3×P(III)^(0.7)+2×(OH)^(0.2)  whereinP(V) is the weight-based content (ppm) of the P(V) compound in terms ofphosphorus atoms, P(III) is the weight-based content (ppm) of the P(III)compound in terms of phosphorus atoms, and OH is the concentration(eq/ton) of molecular terminal OH groups, and which total 5×10⁻⁶ to6.5×10⁻³ parts by weight in terms of phosphorus atoms; and having (C) amelt viscosity change rate at 300° C. of 0.5% or less.
 2. The aromaticpolycarbonate composition of claim 1, wherein the free P(III) compoundand the free P(V) compound satisfy the following expression:0.1×P(III)^(0.5)+0.03(OH)^(0.3)≦P(V)≦3×P(III)^(0.5)+2×(OH)^(0.2) whereinP(III), P(V) and (OH) are as defined hereinabove.
 3. The aromaticpolycarbonate composition of claim 1 which contains the bondedphosphorus atoms and the phosphorus atoms of the free phosphoruscompounds in a total amount of 1.0×10⁻⁵ to 8.0×10⁻³ part by weight basedon 100 parts by weight of the aromatic polycarbonate.
 4. The aromaticpolycarbonate composition of claim 1, wherein the ratio of the bondedphosphorus atoms to the phosphorus atoms of the free phosphoruscompounds is in the range of 1:4 to 4:1.
 5. The aromatic polycarbonatecomposition of claim 1 which contains the free phosphorus compounds insuch amounts that satisfy the following expression (2): 0.1×(P(III))^(0.5)+0.05×(OH)^(0.3)≦P(V) ≦3×(P(III))^(0.5)+1×(OH)^(0.2)  (2) whereinP(V) is the weight-based content (ppm) of the P(V) compound in terms ofphosphorus atoms, P(III) is the weight-based content (ppm) of the P(III)compound in terms of phosphorus atoms, and OH is the concentration(equivalents/ton) of molecular terminal OH groups.
 6. The aromaticpolycarbonate composition of claim 1, wherein the ratio (Mw/Mn) of theweight average molecular weight (Mw) to the number average molecularweight (Mn) of the aromatic polycarbonate (A) is 2.0 to 3.6.
 7. Thearomatic polycarbonate composition of claim 1, wherein the free P(III)compound is a phosphorous acid ester and the free P(V) compound is aphosphoric acid ester.
 8. The aromatic polycarbonate composition ofclaim 1, wherein the free P(III) compound is a phosphorous acid triesterrepresented by the following formula:

wherein R¹ is a t-butyl group, t-amyl group or cumyl group, and R² andR³ are each independently a hydrogen atom, t-butyl group, t-amyl groupor cumyl group.
 9. The aromatic polycarbonate composition of claim 1,wherein the free P(V) compound is a phosphoric acid triester representedby the following formula:

wherein R¹ is a t-butyl group, t-amyl group or cumyl group, and R² andR³ are each independently a hydrogen atom, t-butyl group, t-amyl groupor cumyl group.
 10. The aromatic polycarbonate composition of claim 1,wherein the free P(III) compound and the free P(V) compound have thesame ester moiety skeleton.
 11. The aromatic polycarbonate compositionof claim 1, wherein the acid value of the aromatic polycarbonate (A) is0 to 2 eq/ton.
 12. The aromatic polycarbonate composition of claim 1,wherein some of the molecular terminal OH groups of the aromaticpolycarbonate (A) are capped by a salicylic acid ester.
 13. The aromaticpolycarbonate composition of claim 1 which contains an alkali metalcompound in an amount of 10 to 800 ppb in terms of an alkali metal. 14.Amended) The aromatic polycarbonate composition of claim 1, wherein thearomatic polycarbonate (A) is produced by melt polycondensing anaromatic dihydroxy compound and a carbonic acid diester in the presenceof an ester exchange catalyst which contains (a) a basic nitrogencompound and/or a basic phosphorus compound and (b) an alkali metalcompound or alkali earth metal compound.
 15. The aromatic polycarbonatecomposition of claim 14, wherein the aromatic polycarbonate (A) isproduced by using a melt viscosity stabilizer represented by thefollowing formula (3): A¹—(SO₃X¹)_(m)  (3) wherein A¹ is a hydrocarbongroup having 1 to 20 carbon atoms which may have a substituent, X¹ is anammonium cation, phosphonium cation or alkyl group having 1 to 10 carbonatoms, and m is an integer of 1 to 4, in an amount of 0.7 to 100equivalents based on 1 equivalent of the alkali metal compound of theester exchange catalyst.
 16. An aromatic polycarbonate composition whichfurther contains 0.01 to 0.5 part by weight of a higher fatty acid esterbased on 100 parts by weight of the aromatic polycarbonate compositionof claim
 1. 17. The aromatic polycarbonate composition of claim 16,wherein the higher fatty acid ester is a partial ester of a higheraliphatic carboxylic acid and a polyhydric alcohol.
 18. The aromaticpolycarbonate composition of claim 17, wherein the higher aliphaticcarboxylic acid is a saturated aliphatic monocarboxylic acid having 12to 24 carbon atoms and the polyhydric alcohol is glycerin.
 19. Anaromatic polycarbonate composition which contains 0.001 to 10 parts byweight of a steric hindrance phenol-based stabilizer based on 100 partsby weight of the aromatic polycarbonate composition of claim
 1. 20. Thearomatic polycarbonate composition of claim 1 which has an acid value of0 to 2 eq/ton.
 21. The aromatic polycarbonate composition of claim 1which has a melt viscosity change rate at 300° C. of 0.5% or less.
 22. Amolded article of the aromatic polycarbonate composition of claim 1, 16or
 19. 23. The molded article of claim 22 which is a disk substrate.